Set in the 1860s, the final years of the Tokugawa Shogunate, The Fireflies focuses on Tose (Awashima Chikage), the mistress of the Teradaya, a small inn in the Kyoto suburb of Fushimi. She does not have an easy life. Her husband, Isuke (Ban Junzaburo), is a wastrel who fancies himself a kabuki singer and who is obsessed with cleanliness. Her mother-in-law, Sada (Miyoshi Eiko) dislikes her because of her humble origins (her family are farmers) and because she fears that she will inherit the inn instead of Sugi, her daughter. Sada's hopes for Sugi, however, are dashed when she runs off with a con artist and leaves her child behind for Tose to take care of. When Sada becomes seriously ill, it is Tose who nurses her. On her deathbed, Sada asks her daughter-in-law's forgiveness. Meanwhile Isuke spends most of his time with a mistress he has taken, forcing Tose to manage the inn by herself